When asked about when the show will end, Costner said he doesn't know, but he has no plans on stopping anytime soon.
"No, I don't know how it ends," Costner maintained before admitting that he'd want to know.
"I am going to end if it doesn't end," he quipped.
All jokes aside, Costner, who plays Montana rancher and Dutton family patriarch John Dutton, said he's along for the ride until the show no longer feels "interesting" to him.
"I'll go till it doesn't feel like we're interesting, and right now we have our foot on the gas and that feels OK to me. I have interests that are outside of everything I do, including the movies, so I have other things that I want to do," Costner said about when he'd be ready to step outside the Yellowstone universe.
As far as what's next for him, Coster said there's still a lot he needs "to learn."
"I just feel like, listen, when I was younger, I grew up in such a conservative way. I actually thought the world was flat," the 67-year-old actor admitted. "I mean, I didn't know what was possible for me -- I came up with a really good foundation, but I I thought there was a lot that I needed to learn. There's a lot that I still need to learn."
Costner continued, "I mean, what I will regret when I do leave, shuffle off, you know, it's probably books I'll never have read, and songs I'll never have heard, the stories. There's stuff left."
With season 5 in the works, there's a host of Emmy buzz around the show. While Costner is happy to receive the recognition, he said the most important thing to him is doing good work that's important to you.
"I think we've been doing the same work from the first season, and I think that's number one -- been really important to me.The recognition comes -- the writing has to stay strong. Keep doing what we're doing, and then people catch up to you in your life," Costner shared. "I've always said, it's not too hard to be popular, you can do a lot of things to get noticed or whatever, but if you're trying to be relevant in your own life, you maybe have to be doing the things you feel like are important to you. If the world gets in sync with your life, how great is that? But if you're always chasing an idea that's already working, and put a spin on it, there's a business to that."
He continued, "And that's done all the time and there's nothing really wrong with it, but it's not the way I can conduct myself. When I found Yellowstone, it hadn't been made. I liked the story, I thought we could do this, so, the idea that it's good, that doesn't surprise me at all. The idea that it blew up, that's something you can’t always predict."
See Costner and the rest of the Dutton family when Yellowstone returns to Paramount+ for season 5 on Nov. 13.